Torque Transmission Device Useful as a Fixed Constant Velocity Ball Joint for Drive Shafts and Method for Producing Such a Joint

Abstract

A torque transmission device such as a fixed constant velocity ball joint constructed as an opposed track joint and a process for producing such a device, in which the curvatures bases of the tracks of the joint deviate in their axial course from the curvatures of the ball contact lines. The process is characterized in that prior to the formation of a longitudinal profile of the joint component, the component is brought to an increased hardness by a hardening process and a diffusion layer is partially or completely removed in the region of the longitudinal profile.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of international patent application no. PCT / DE2007 / 001183, filed Jul. 5, 2007 designating the United States of America and published in German on Jan. 10, 2008 as WO 2008 / 003303, the entire disclosure of which is incorporated herein by reference. Priority is claimed based on Federal Republic of Germany patent application nos. DE 10 2006 031 002, filed Jul. 5, 2006; DE 10 2006 037 847, filed Aug. 12, 2006 and 10 2007 030 898, filed Jul. 3, 2007.BACKGROUND OF THE INVENTION[0002]The invention relates to a torque transmission unit having at least one component for transmitting torques via each of two functional areas formed onto the component and causing the torque flow by a formfitting engagement with other elements, at least one of the two functional areas being constructed as a profile, such as longitudinal teeth.[0003]Torque transmission units of this type are disclosed, for example, in U.S. Pat. No. 6,8...

AI Technical Summary

Benefits of technology

"The present invention relates to torque transmission devices, such as fixed, constant velocity joints, which require high strengths and the transmission of high torque with high precision. The invention aims to provide cost-effective and efficient production of these devices while improving their quality and performance. The invention achieves this by optimizing the strengths of the components, reducing the wear of the machines, and ensuring the precision of the ball raceways and the calibration process. The invention also allows for the production of internal and external joint parts with reduced investment costs and improved quality. The invention also provides a solution for the production of components with longitudinal teeth and ball raceways, which are hardened to achieve higher torque transmission values. The hardening process results in a lower hardness in the longitudinal teeth but a higher hardness in the areas where the teeth are formed, which can be advantageously used in a cost-effective surface hardening process. The invention also provides a method for producing components with two different functional areas for transmitting torque which are formed on the component and cause the torque flow by formfitting engagement, one of which is constructed as longitudinal teeth and the other being, for example, the raceways for the balls of a joint. The formed-on ball raceways may or may not be subject to machining, and the invention distinguishes between these two alternatives."

Problems solved by technology

This is advantageous for producing longitudinal teeth, but does not permit the high torque values to be transmitted and the desired service life to be achieved, which are required in many cases.

Another known possibility is to first manufacture the teeth in the soft state, to case-harden the entire part, i.e., having formed-on longitudinal teeth, which results in hardening distortion of both the teeth and also the spline teeth, however, which may only be remedied in the longitudinal teeth with additional great effort, namely by hard broaching in the hard layer using corresponding suitable, but costly special machines and tools, for example.

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